Universal Mobile Telecommunications Service (UMTS) is a third generation (3G) broadband cellular wireless standard. The Radio Link Control (RLC) sublayer of the UMTS standard includes an Acknowledged Mode (AM) of operation that supports an Automated Repeat Request (ARQ) function that provides for retransmissions of lost or erroneous data units. In its present form, the Acknowledged Mode of the RLC sublayer includes inefficiencies in the use of available bandwidth resources. There is a need for techniques and structures for enhancing the efficiency of the RLC sublayer of the UMTS standard and of similar communication protocols.